A front support link and a rear support link for supporting the seat cushion are respectively arranged in a front portion and a rear portion of the outer side (window side) and the inner side (vehicle room inside) of the seat for a vehicle. These support links constitute one portion of the height adjusting mechanism.
The front support link and the rear support link are connected between a floor side member (link) and a seat side member (link), and constitute a four-joint rotating chain (link mechanism) together with the floor side member and the seat cushion side member.
Further, a driving mechanism portion for tilting a rear support link (a front support link can be also set) is assembled onto one of the outer side and the inner side (the outer side is set in the following explanation). The rotation of the rear support link of the outer side is transmitted to the link mechanism of the inner side through a transmission rod so that the operations of the link mechanisms on both the sides are synchronized.
Namely, the link mechanism of the outer side of the seat is directly operated by the driving mechanism portion. The link mechanism of the inner side is operated by following the link mechanism of the outer side through the transmission rod.
At a time of collision of the vehicle, a colliding load (inertia force) applied to the seat is transmitted from the seat cushion side to the front support link and the rear support link of the link mechanism on the outer side and the inner side.
At this time, in the link mechanism of the outer side assembling the driving mechanism portion thereinto, the driving mechanism portion supports the colliding load so that the rotations of the front support link and the rear support link can be prevented. However, in the link mechanism of the inner side, the colliding load is applied as force for twisting the transmission rod. Accordingly, the transmission rod is twisted and the front support link and the rear support link are correspondingly rotated.
Therefore, when the vehicle collides forward (forward collision) and a large colliding load is applied to the seat, the front support link and the rear support link are rotated forward in the link mechanism of the inner side, and the seat cushion is projected forward. Conversely, when the vehicle collides backward (backward collision), the seat cushion is sunk backward.
It is known that a colliding stopper is arranged in the link mechanism of the inner side to prevent such a movement of the seat cushion. The colliding stopper shown in FIGS. 1 and 2 has teeth attaching segments (engaged members) 101, 102 forming plural teeth arranged on the seat cushion side, and a claw lever (engaging member) 104 rotatably arranged in a support link 103 and having teeth able to be engaged with the teeth of the teeth attaching segments 101, 102. The colliding stopper further has a lock hole 105 and a lock spring 106 for biasing the claw lever 104 in the direction of the lock hole 105. The lock hole 105 is formed on the side of the support link 103, and is engaged with the claw lever 104, and inhibits the further rotation of a direction separated from the teeth attaching segments 101, 102 of the claw lever 104 in a position in which no teeth of the claw lever 104 are engaged with the teeth of the teeth attaching segments 101, 102.
When the colliding load is applied to the seat, the claw lever 104 is rotated against the biasing force of the lock spring 106 by inertia, and is engaged with the teeth attaching segments 101, 102. The rotation of the support link 103 is inhibited by this engagement of the claw lever 104 and the teeth attaching segments 101, 102, and the movement of the seat cushion is also inhibited.
Patent literature 1: JP-T-2003-513850